Guys....this is really hard to post. IF you see signs...this is the end of the life of the fish. Meds prolong the pain. Please just destroy the fish and throw out all decor. Bleach may or may not rid this. I talked to my Vet and got some major strength cleaner that human labs use. All my tanks except 3 are contaminated through my plants. This should NOT be taken lightly.

I think one of the issues is that the symptoms can vary a lot, which means it may not apparent that a fish is suffering specifically from Mycobacterium infection.

According to information in the link I posted above, bleach is NOT effective at killing Mycobacteria. It has a waxy coating that protects it. To kill Mycobacteria, a disinfectant, such as Lysol, is needed.

(This has me worried, since I think my male HM died from this. I cleaned the tank with bleach, and put my new HM into it. He became ill last night....)

But I still don't understand why this would affect primarily BLUE fish?

i would think it has something to do with the blue gene...maybe a trait carried on it that was dormant and just started up recently with the new breeding and kinds out there.thats my opinion.but with not knowing much about it.it could be anything really.im baffled myself

Does anyone know the minimum incubation period for Mycobacterium infection?

Could a fish become ill after 4 days of being exposed? (If so, I may have a non-blue with it.)

I did some research, and the answer appears to be that no, a fish wouldn't become ill after just 4 days. There are some forms of Mycobacteria that are faster growing than others, but even the faster ones aren't that fast.

I got my diagnosis today. It IS Mycobacterium! This is what is considered fish TB (but from the Lab Manager....it is NOT TB!!!!!!!) Which verity is unknown because it would have cost me 3x as much as I'm gonna have to pay (which that is still unknown). The rot is a secondary infection...the fish is dying so the fins go first.....

Here's what I found:

It is not called TB because this is specifically reserved for Mycobacterium tuberculosis, which causes TB in people, but does not affect fish.

There are several types of Mycobacterium that do affect fish. As a group, they're just called “atypical mycobacteriosis," and all fish are susceptible to them (to one degree or another). It results in a chronic and progressive disease. However, the symptoms and signs can vary widely, so there is no "typical" presentation.

Mycobacterium thrives in warm water temperatures, that have low dissolved oxygen levels, acidic pH, and and lots of organic material.

In the lab, classifying the organism as Mycobacterium is relatively straightforward. However, determining the exact species is a more involved process. (This is why it costs a lot more.) Different species grow at different rates, under different types of conditions, etc.

However, it doesn't really matter what species is present, because: "Mycobacterial infections of all fish should be considered non-treatable. Although there are some research reports of aquarium fish responding to antibiotic therapy, individual fish have not been cured of the disease. Symptoms may resolve temporarily but often reappear when antibiotics are discontinued. As described for food fish, depopulation and disinfection of all contaminated equipment is recommended."

Mycobacterium is a very slow moving illness, that can be treated but is also very difficult to treat. It is probably the most difficult disease to treat. The meds have to go internal and the treatment can take up to a month. Kanaplex is probably most effective. Also adding vitamin b supplements to the water can also be helpful as it helps boost their immune system. I've used Vitachem. This fast rot thing is NOT Mycobacterium, although TB fish may get a secondary infection as the fish TB weakens the immune system, and that infection could be this fast rot thing. Not every fish with this rot is battling TB too.

I'm afraid this fast-moving disease IS mycobacterium because there is a positive lab result. It is NOT fish TB though. According to one of my sources, there are supposedly only two strains of mycobacterium that affect aquarium fish, m. marinum and m. fortuitum. However, that particular source, while still offering outstanding advice, is also slightly out of date (published in 1998). Another more up to date book says there is also mycobacterium chelonae.

According to this book, any of the three mycos can cause the symptoms that we identify as fish TB (the wasting, the spinal deformity, the ulcers). There is an average incubation period of roughly 6 weeks before the onset of symptoms.

Although we have a positive diagnosis, I'm still very much perplexed by the symptoms caused and by the targeted fish. I feel like some more research still need to be done. What if we are facing a new strain of myco that exhibits entirely different symptoms? As Callistra noted, myco or fish TB is usually a slow-moving, wasting disease. This comes on and kills in usually 24 hrs.

It doesn't appear to be the "rot" that is killing the fish. Rather, since myco attacks internally with granulomas that attach to the stomach walls and other organs, it would appear an inner battle is taking place that we don't know about until it reaches critical. If a granuloma bursts and the infection reaches the bloodstream, this may cause the rapid downturn that we see. The rot or necrosis is most likely a side effect of the internal organs dying in what is probably an unpleasant manner.